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标题: 我的虚拟接口通过netif_rx传包，上层协议似乎收不到 [打印本页]
作者: pqy330    时间: 2017-06-29 15:57
标题: 我的虚拟接口通过netif_rx传包，上层协议似乎收不到
  1. #include <linux/module.h>
  2. #include <linux/init.h>
  3. #include <linux/device.h>
  4. #include <linux/string.h>
  5. #include <linux/slab.h>
  6. #include <linux/module.h>
  7. #include <linux/netdevice.h>
  8. #include <linux/kernel.h>
  9. #include <linux/etherdevice.h>

  11. struct net_device *virtualNIC;

  13. int virtualNIC_open(struct net_device *dev) {
  14. printk("virtualNIC_open called\n");
  15. return 0;
  16. }

  18. int virtualNIC_release(struct net_device *dev) {
  19. printk("virtualNIC_release called\n");
  20. netif_stop_queue(dev);
  21. return 0;
  22. }

  24. int virtualNIC_xmit(struct sk_buff *skb, struct net_device *dev) {
  25. printk("dummy xmit function called...\n");
  26. dev_kfree_skb(skb);
  27. return 0;
  28. }


  31. int virtualNIC_init(struct net_device *dev) {
  32.   printk("virtualNIC device initialized\n");
  33.   return 0;
  34. };
  35. const struct net_device_ops my_netdev_ops = {
  36.      .ndo_init = virtualNIC_init,
  37.      .ndo_open = virtualNIC_open,
  38.      .ndo_stop = virtualNIC_release,
  39.      .ndo_start_xmit = virtualNIC_xmit,
  40. };

  42. //static void ether_setup(struct net_device *dev){
  43. //  dev->netdev_ops = &my_netdev_ops;
  44. //}


  47. int virtualNIC_init_module(void) {
  48. int result;
  49. char mac[6] = {0x12,0x34,0x56,0x78,0x90,0xab};
  50. virtualNIC = alloc_etherdev(0);
  51. if(!virtualNIC){
  52.      return -1;
  53. }
  54. virtualNIC->netdev_ops = &my_netdev_ops;

  56. memcpy(virtualNIC->dev_addr, mac, virtualNIC->addr_len);
  57. if((result = register_netdev(virtualNIC))) {
  58.   printk("virtualNIC: Error %d initalizing card ...", result);
  59.   return result;
  60. }
  61. return 0;
  62. }


  65. static ssize_t vnet_recv(struct class *cls, struct class_attribute *attr, const char *_buf, size_t _count)
  66. {
  67.     struct sk_buff *skb = dev_alloc_skb(_count+2);
  68.     if(!skb){
  69.         printk("Out of mem!\n");
  70.         goto out;
  71.     }
  72.     skb_reserve(skb, 2);
  73.     memcpy(skb_put(skb, _count), _buf, _count);
  74.     skb->dev = virtualNIC;
  75.     skb->protocol = eth_type_trans(skb, virtualNIC);
  76.     skb->ip_summed = CHECKSUM_UNNECESSARY;
  77.     //skb->pkt_type = PACKET_HOST;
  78.    
  79.     printk("%d %d %d\n",skb->pkt_type, ntohs(skb->protocol), netif_rx_ni(skb));
  80. out:   
  81.     return _count;
  82. }

  84. static struct class *vnet_class = NULL;
  85. static CLASS_ATTR(recv, 0220, NULL, vnet_recv);
  86. int __init vnet_init (void)
  87. {
  88.     virtualNIC_init_module();
  89.     vnet_class = class_create(THIS_MODULE, "vnet");
  90.      if (IS_ERR(vnet_class))
  91.     {   
  92.         printk("Create class vnet_class failed.\n");
  93.         return -ENOMEM;
  94.     }
  95.     class_create_file(vnet_class, &class_attr_recv);
  96.     return 0;
  97. }

  99. void __exit
  100. vnet_exit (void)
  101. {
  102.   class_remove_file(vnet_class, &class_attr_recv);
  103.   class_destroy(vnet_class);
  104.   unregister_netdev(virtualNIC);
  105.   free_netdev(virtualNIC);
  106.   vnet_class = NULL;
  107. }

  109. module_init (vnet_init);
  110. module_exit (vnet_exit);


  113. MODULE_AUTHOR("None");
  114. MODULE_LICENSE ("GPL");
复制代码


我注册了个netdev, 以及sys一个入口文件，应用层负责构建完整的以太网帧写到入口文件，然后模块把这个以太网帧传给内核。wireshark抓包看包很正常，各项参数都对，目的mac是我的虚拟接口的，ip checksum，udp checksum都对，但是应用层的udp socket收不到。netif_rx返回0.  求大佬指教哪里有问题。
作者: pqy330    时间: 2017-06-29 21:53
用gdb跟踪到问题了，dest ip 不能是127.0.0.1, 否则被丢掉



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